Title
The Origin of [CII] 157 μm Emission in a Five-component Interstellar Medium: The Case of NGC 3184 and NGC 628
Author
Abdullah, A. (Universiteit Leiden)
Brandl, B.R. (TU Delft Astrodynamics & Space Missions; Universiteit Leiden)
Groves, Brent (Australian National University)
Wolfire, Mark (University of Maryland)
Calzetti, D. (University of Massachusetts Amherst)
Croxall, Kevin (Ohio State University)
Looze, Ilse De (University College London (UCL); Universiteit Gent; University of Cambridge)
Kennicutt, R. C. (University of Cambridge)
Sandstrom, K. M. (University of San Diego)
Armus, Lee (Spitzer Science Center)
Dale, Daniel A. (University of Wyoming)
Galametz, Maud (European Southern Observatory)
Herrera-Camus, Rodrigo (University of Maryland; Max Planck Institute for Extraterrestrial Physics Garching)
Hunt, L. K. (INAF-Osservatorio Astrofisico di Arcetri)
Smith, J. D T (University of Toledo)
Tielens, A. G.G.M. (Universiteit Leiden)
Date
2017-06-10
Abstract
With its relatively low ionization potential, C+ can be found throughout the interstellar medium (ISM) and provides one of the main cooling channels of the ISM via the [C ii] 157 μm emission. While the strength of the [C ii] line correlates with the star formation rate, the contributions of the various gas phases to the [C ii] emission on galactic scales are not well established. In this study we establish an empirical multi-component model of the ISM, including dense H ii regions, dense photon dissociation regions (PDRs), the warm ionized medium (WIM), low density and surfaces of molecular clouds (SfMCs), and the cold neutral medium (CNM). We test our model on ten luminous regions within the two nearby galaxies NGC 3184 and NGC 628 on angular scales of 500-600 pc. Both galaxies are part of the Herschel key program KINGFISH, and are complemented by a large set of ancillary ground- and space-based data. The five modeled phases together reproduce the observed [C ii] emission quite well, overpredicting the total flux slightly (about 45%) averaged over all regions. We find that dense PDRs are the dominating component, contributing 68% of the [C ii] flux on average, followed by the WIM and the SfMCs, with mean contributions of about half of the contribution from dense PDRs, each. CNM and dense H ii regions are only minor contributors with less than 5% each. These estimates are averaged over the selected regions, but the relative contributions of the various phases to the [C ii] flux vary significantly between these regions.
Subject
galaxies: ISM
To reference this document use:
http://resolver.tudelft.nl/uuid:9f9c8963-9bfb-4a01-bc86-ac66a2e334ff
DOI
https://doi.org/10.3847/1538-4357/aa6fa9
ISSN
0004-637X
Source
The Astrophysical Journal: an international review of astronomy and astronomical physics, 842 (1)
Part of collection
Institutional Repository
Document type
journal article
Rights
© 2017 A. Abdullah, B.R. Brandl, Brent Groves, Mark Wolfire, D. Calzetti, Kevin Croxall, Ilse De Looze, R. C. Kennicutt, K. M. Sandstrom, Lee Armus, Daniel A. Dale, Maud Galametz, Rodrigo Herrera-Camus, L. K. Hunt, J. D T Smith, A. G.G.M. Tielens